1. Field of the Invention
The present invention relates to increasing the compression in one cylinder commencing its compression stroke by utilizing the residual energy or pressure of the exhaust gases in a complemental cylinder.
2. Description of the Prior Art
In a four-stroke cycle internal combustion engine, the cycle consists of a suction or intake stroke which draws air or a mixture of fuel and air into the cylinder, depending upon whether the fuel is drawn in through a carburetor or is injected. The drawing in of the fuel/air mixture develops a vacuum which typically amounts to 21 inches.
The cycle also includes a compression stroke during which the mixture of air and fuel is compressed within a combustion chamber which gradually reduces in size; and a power stroke following ignition of the charge, the pressure in the cylinder on completion of the power stroke typically being in excess of approximately 45 psi. The final stroke of the cycle is the exhaust stroke which expels the burned charge from the cylinder. Since four piston strokes are required to complete a cycle, there is one power stroke for each two revolutions of the crankshaft and, in engines having an even number of cylinders, the cylinders are arranged in complemental pairs. For each pair, ignition occurs alternately at intervals of 360 degrees of crankshaft rotation, with the pistons of the cylinders thus reciprocating in unison in the same direction, but on different strokes.
It is known to interconnect a complemental pair of cylinders whose pistons are reciprocating in unison in the same direction but on different strokes, as disclosed in U.S. Pat. No. 4,033,302, issued July 5, 1977. However, the system of that patent was designed to provide fuel injection. The interconnecting conduit was connected to a source of fuel and the higher pressure existing in a cylinder on its power stroke was utilized to inject fuel through the conduit into a complemental cylinder beginning its compression stroke.
Interconnection of a pair of complemental cylinders is also disclosed in U.S. Pat. No. 3,974,804, issued Aug. 17, 1976. In that case, interconnection was for the purpose of utilizing the residual energy of the exhaust gas of one cylinder to supercharge the other cylinder. However, scavenging of the connecting conduit was proposed to be accomplished by providing integral passageways in the pistons. Scavenging air from a blower was applied to the passageway in one piston for passage through the connecting conduit, and for discharge through the passageway in the complemental piston. The system thus required specially formed pistons and no suggestion was made respecting prevention of what would appear to be relatively high rates of air flow past the piston skirts and into the crankcase.
Thus, there appears to be no teaching in the prior art of a system for utilizing, without radically modifying the structure of the pistons, the residual energy of exhaust gases in one cylinder to supercharge a complemental cylinder whose piston is reciprocating in unison with the first cylinder, but on a different stroke, thereby to improve compression and consequently engine fuel economy.